


Pills and Potions

by yawnfics



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: Anal Fingering, Anal Sex, Aphrodisiacs, Fake Science, First Time Topping, Fluff and Smut, Fuck Or Die, Gay Sex, I think that’s it, Kinda, Light Angst, M/M, My best work by far, Orgasm Delay/Denial, Other Additional Tags to Be Added, Overstimulation, Porn With Plot, Porn with Feelings, Smut, Tags Are Hard, Virgin Senku, blowjob, bottom Gen, chemical use, top senku, we love it here, well more like gone wrong
Language: English
Status: Completed
Published: 2020-04-17
Updated: 2020-04-17
Packaged: 2021-02-23 06:35:36
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,721
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23707249
Author URL: https://archiveofourown.org/users/yawnfics/pseuds/yawnfics
Summary: Asagiri Gen doesn’t know all the details but apparently something went very wrong while Senku was in the lab. In the midst of confusion he hears Senku muttering something about, “accident” “aphrodisiac” and “inhaling large quantities” but none of that really makes sense as to why Senku is curling in on himself on the floor almost prostrating himself to Gen. He really shouldn’t be here but dear Senku really looks like he needs help.
Relationships: Asagiri Gen & Ishigami Senkuu, Asagiri Gen/Ishigami Senkuu
Comments: 13
Kudos: 301





	Pills and Potions

**Author's Note:**

> This..um...this was in the drafts for 5 months. The science aspect of this may not be entirely correct because I’m a business major LMAO but no pls if it sounds weird just bear with it. The mysterious root is a Maca root which I GOOGLED along with the chemicals and I never do research so this is pretty new for me. Please enjoy
> 
> -Any events or characters that occur in the passage below are merely FICTIONAL and have no connection to anyone or anything in the real-world. Please note that any replicas of this work without due credit are not tolerated and must be taken down-

The Village is in its age of peace and tranquility because the harsh Winters have passed. Everyone is out planting whatever they can get their hands on so that the fields are filled with crops for the next few months. Gen sits in his Spring hut fiddling with the hole in his robe because he doesn’t have anything in particular to do. These days it strangely feels like he’s losing his purpose in life regardless of what others say. He can only think of so many uses that only a mentalist can have and in the long-run, he sees himself being obsolete. He doesn’t have any super smarts like Senku, no super craftsmanship like Kaseki, and no super fighting skills like Kohaku. Don’t get him wrong, he’s not entirely useless, but all he does is puppeteer people into doing what’s best for the Kingdom of Science or whoever he sees fit. With the limited supplies and options, he’s finding _that_ harder to do. 

  
  


He can’t entertain himself like he used to and he certainly can’t relax how he wants to. Normally, when he gets in this somber mood, he’d pop open a cold soda and plop his feet up to watch reruns of his favorite sit-com and life would be better again. He also wasn’t necessarily a family man but the occasional phone call from his mother would brighten his day. He’s always been fully aware that he’s going to die one day but now without the Grand Finale. He wanted his name in headlines as all of his fans burned candles to help him pass...it was a simple dream, honestly. 

  
  


He sighs to himself as he stands, the weight of existence making each movement difficult to perform but he eventually pushes through. With his signature smile plastered on his face, he exits the hut with his arms neatly tucked into the opposite sleeve. He needs some form of excitement so he decides to go bother Senku. Surely the radish head would have something new he’s trying.

  
  
  
  
  
  
  
  


Senku is a smart man. That he is. But he is also an impulsive man when it comes to concoctions. It’s not something he’s proud of, but when he gets his creative juices flowing, he can’t help but try any and every combination. Right now, he’s _supposed_ to be making a corrosive that he can use to break down some items for their next project. 

  
  


When he sees compounds laid out before him, he has a habit of mentally combining them and estimating their probability of working in this stone world. This is exactly what he’s doing as he eyes down the ingredients for his hydrochloric acid and this onion-shaped root that Suika brought him earlier. He’s basically finished with his first objective so why not toy around with something else?

  
  


He minces and dices the root until very fine and sets it in a dish separate from everything else. If the root is what he thinks it is, then this may just be a weapon of the ages. It honestly takes everything in him not to cackle like a literal mad scientist. He then begins to soak the root in water, and then straining the water to reuse the minced pieces. He repeats this process several times so that the solution contains as many traces of the root as possible. 

  
  


He then carefully pours the solution into his chemical solution. Aside from the small details of a minor reaction taking place, nothing happens. The liquid turns from light brown to almost purplish? “Snoozefest” is one of the first things he thinks before grabbing some more hydrochloric acid.

  
  


Really, he didn’t even add that much. What happened shouldn’t have happened but it did and now he thinks he’s dying. His vision disappears completely as the concoction literally explodes in a plume of smoke with a dangerously sour smell. 

  
  


Fuck. He shouldn’t have inhaled that. 

  
  


Wow, this is really how he’s going to go out? He could hear the village gossiping now…”Senku died in an explosion trying to make a war-based sex drug, now _that’s_ sorcery for you.” Well the jokes on them because he doesn’t intend to end things here. He manages to get some of his bearings as he flings himself out of the small lab space and nearly breaks several bones on his way down but he’s fine! From what his bleary eyes can see, there’s a thin purple mist coming from the station. That is definitely going to have to be explained to the villagers but maybe not when his rib cage is on fire.

  
  


He thinks he hears his name being called but most of the other villagers should be planting food for the spring and summer months which automatically means his science crew should be there helping out as much as they can anyways. Shit his lungs sting. During all of his life, he’s never really been athletic but this sting hurts worse than running 3 laps during his middle school physical education class. He’s also very...warm? No. Hot. Definitely hot. But spring isn’t even in full effect yet. What day is it again?

  
  


His head is obviously about to fall off in the next few seconds. Whatever side-effect that failed weapon had is attacking his senses and it’s coming in strong. The feeling in his legs is near numb and he can feel all his muscles relaxing. There is a dopey grin creeping on his face and he wants to fight it off—believe him, he does—but it’s an impossible battle. His heart is jacking out of his chest and his gaze is twice as unfocused. There’s a throbbing...somewhere, but he can’t pinpoint where right now. Right now he wants to sleep, and maybe eat ice cream but mainly sleep. His eyes droop as if he’d been awake for four days straight and he lets them. 

  
  


Right before he nods off he swears he sees a glimpse of white and black hair. 

  
  
  
  
  
  
  


Oh dear. Senku-chan is dead. There’s no way he can‘t be with the way he’s sprawled out the grass. Gen takes note of the ominous gas coming from the work lab and the awful stench it left behind. Senku has gone and blown himself up and he didn’t even get to say goodbye. How sad. As Gen leans closer to Senku’s corpse, he starts to plan an extravagant funeral that only he could plan because it’s the least he could do for- 

  
  


He nearly jumps out of his skin as Senku’s supposed corpse coughs violently before remaining still. How strange maybe he was alive! But then again the body is still active for 15 minutes after death or something like that. He didn’t really pay attention to that lecture in school. Taking a deep breath, he steels his nerves and reaches over to check his friend’s pulse and nearly slumps over in relief when he detects one. 

  
  


Thank the heavens above. Now the village won’t be forced into a recession. Their Einstein was alive but now to make sure he stays this way. Gen isn’t the strongest but he’s afraid that in the time he does take to retrieve the resident meatheads, Senku’s respiratory system would have failed or even worse... he would’ve gotten nabbed by a giant prehistoric bird. Anything could happen out here. 

  
  


His back creaks and cracks with the effort but he manages to carry Senku all the way to his humble hut. For a man with the body mass of a high school girl, his unconscious weight was _nothing_ to giggle at. The magician crouches before the slouched man and waves a hand in front of his face for good measure. Out completely cold. Now he wasn’t a medic or anything but the bluish bruises on the man's shoulder didn’t look too healthy. He’d have to go into the village once Senku woke up to get the right herbs for that. 

  
  


For now he was content staring. 

  
  


At what? He had no idea but his previous boredom led him to seeking the young science freak but now that his wish was granted, he hoped it would’ve been under different circumstances. He scanned over Senku’s unconscious body looking for any more injuries and surprisingly found none. He was lucky enough not to have literally been blown to pieces considering no one was around to immediately get him the help he needed. Gen was in no place to scold him but you’d think he’d be a little less reckless when playing with these things came with very, very limited medicine. 

  
  


He had settled for counting the stitchings on Senku’s gown when the boy twitched. It was slight at first but then progressed into a small convulsion. Gen’s panic returned immediately and he kneeled over the jittering body as he laid a hand on his chest. He shook him a little but nothing happened. He shook him a little bit harder but nothing happened. _Sorry dear friend_ was the last thing he thought before slamming his palm down on the scrawny chest beneath him. 

  
  


Senku coughed to life and apparently brought a string of curses with him. He rubbed at his sizzling chest and narrowed his eyes at his perpetrator. What a lovely wake up call. Not only was his body suffering in more ways than one, he probably had a human hand print in the middle of his pale chest. He appreciates Gen, he truly does, but his pain can only be coupled with his annoyance. Senku sits up and lets the remains of his drowsiness roll off of him in waves.

  
  


His shoulder hurts like hell but he wasn’t in terrible shape. He tried to stand on his legs but apparently they’re the only thing that hadn’t fully recovered from the shock. 

  
  


“Gen-”

  
  


“Yes, Senku-chan?”

  
  


“I need to make sure nothing in the lab has set on fire as a result of the chemicals but my legs are super no good right now so you’re going to go for me. There are three beakers that should be sitting in close proximity to each other but I want you to move them _way_ apart.”

  
  


Gen nods and assures Senku that he can handle this task and even promises to come back immediately if the strange smoke hasn’t disappeared yet. This certainly was nothing like the tasks he originally wanted to do but oh well. A task was a task and Gen was determined to be of use. He set off on his hike back to the lab and could see even from this distance that it was somewhat intact. Senku’s grand descent had done nothing but shift some of the decor from the entrance and maybe two steps were missing. Absolutely nothing they couldn’t fix. 

  
  


“I’m no sciencer but even I don’t think this was entirely meant to happen,” Gen mumbles to himself as he climbs up the ladder to observe the state of things. Most of the smoke had cleared out indeed but it had left behind an eye-watering aroma. Something sickly sweet and deathly sour permeated the tower and he would have to push through it just to get to the beakers. Using one hand to cover his face and the other to rearrange everything to ensure that it won’t combust proved as difficult as it may seem. His coughing echoed through the small workspace and he nearly lost his grip on the last container. 

  
  


“Uh-oh!” He shouted before expertly catching it with both hands. He grinned to himself before setting it down again with a mock bow. Now _that_ was a magic trick for the ages. The moment was short-lived as the pungent aroma quickly reminded him that he had better things he could be doing. Gen took one more glance at the room before hightailing it out of there with fervor. You couldn’t pay him to stand in there for any longer than what he did, but enough complaining. He has another mission to complete: help heal Senku.

  
  


The walk back to his little hut is almost silent aside from the grass rustling with the afternoon wind. He hums to himself while walking at a moderately fast pace. It's not like he’s eager to talk to Senku, no! He’s just in dire need of entertainment. Yes, that’s correct, he is just relieving his boredom. He mentally repeats this to himself like a mantra but each time he does, his heart feels a little heavier. Is this really just a means of satisfaction? Technically, he’s leeching off of his dear friend’s efforts but no one else sees it this way...right? He has plenty of things that need his immediate attention but he’s choosing to do something else..right _?_

  
  


There it is again. That depressive attitude that springs forth the moment he doesn’t have anyone to pester. His smile falters and his eyes run cold and unfocused. It’s a little harder to breathe than before so maybe it’s residual something from the lab? But his throat is also getting tighter by the moment so maybe not? He doesn’t know for sure so— _oh!_ Rain? How strange during this early in the year! He chuckled quietly to himself for a minute before collapsing to his knees.

  
  


He was tired of lying to himself.

  
  
  


Tired of lying to others.

  
  


He sat there maybe 300 feet from his hut and cried until his heartache eased into something else. Not happiness, no but something lighter than what it was previously. He could only pray that Senku couldn’t hear his pathetic sobbing from this distance. Surely he could pass it off as Suika whining about a scraped elbow or something. Bottling up things like this did hurt to some degree but he had to keep going for the sake of science. 

  
  


“For the sake of humanity.”

  
  


Gen hoists himself up like a zombie, does a post-cry stretch and _damn_ it feels good. His vision increases tenfold once he wipes the tears from his eyes and his smile this time is genuine. His name is Asagiri Gen and he’ll be damned if he can’t find any way to serve purpose. He’ll make his own fucking purpose and there’s nobody on this land that can tell him otherwise.

  
  
  
  
  
  
  
  


Gen’s cheery attitude is slammed out of him the instant he enters his hut. 

  
  


He’s stumbling over his tongue and his skin is flushed. It’s only scorching in the room because his adrenaline is kicking up a storm. 

  
  


Senku-chan is—

  
  


No, this man wasn’t Senku-chan.

  
  


Who the hell was this? 

  
  


On the woven mat beneath him lay this...this Senku shaped man was writhing in what appeared to be pain. Gen drops next to him and lays a hand on his shoulder and this seems to comfort him for the time being. Before Gen can even open his mouth to demand his identity, the man looks up and locks eyes with him. It’s definitely Senku and he’s in agony.

  
  
  
  
  
  


Senku feels hot. As hell. 

  
  


The moment Gen left is when his fever kicked in but it didn’t stop there. For a few moments he felt like he would throw up so he stuck his head outside the tent as a minor precaution. This feeling didn’t even last long as he fell face-forward because vertigo was kicking his pale ass like you’ve never seen. He broke out in a cold sweat trying to lift himself up and back in the tent but the effort made his already sparse muscles feel like jelly. He was only able to flop back inside and rise to his knees. His ass was propped up in front of the entrance and he would’ve laughed at the surprise set up for Gen if his chest wasn’t burning. 

  
  


There were also some other small issues that he could list off without a hitch but the main problem brought even more heat to his face. He was hard. And no, he wasn’t experiencing some half chub from all of the blood collectively trying to pool anywhere it could. He was rock solid, and throbbing to the point of embarrassment. Senku was basically a grown man, of course he’s experienced a boner here and there, it was only biologically human. But this...this was a feeling that was just as painful as it was pleasurable. 

  
  


His insides were churning now that he had finally acknowledged his killer erection. His everyday cloak had little-to-no coverage so he could feel his stiff cock pressing into the soft fabric with every minute movement. He grit his teeth together to stifle any incoming moans because _god_ did it feel good. Every earth-shattering breath made his vision blur as his perky nipples rustled against the tent’s floor. It sounded extremely morbid but he hoped that Gen died from inhaling those stupid chemical fumes because he did not want to be seen like this.

  
  


God fucking dammit.

  
  


Senku could hear his ridiculous humming before he even made it to the hut. He quickly contemplated feigning passing out again but it’s probably better to just get this over with. The hut’s flaps fly open and he barely has time to open his mouth before Gen shrieks and kneels beside him. His hands are suddenly caressing Senku’s back in comfort and this time he can’t help the mewl that escapes from his lips. There’s an awkward pause and Senku decides to break it for the sake of not going insane. 

  
  


“I’m 10 billion percent sure that the mixture that I was making in the lab is a super aphrodisiac. The maca root I diluted was more flammable than I realized and when it exploded, the gas ended up serving its purpose but I inhaled entirely too much…”

  
  


Gen was trying to follow along, he really was but poor Senku-chan was sweating buckets and his words tended to slur the longer he spoke. He’d managed to hear out the words “accident” “aphrodisiac” and “inhaling large quantities” but that’s all background noise compared to the sight in front of him. 

  
  


“Senku, does it hurt anywhere? What can I do to help?” He asks while simultaneously flipping the said man over so that he was lying on his back. Senku gasped abruptly and threw his arms down to cover his torso. Gen was confused until his eyes traveled down to where he locked eyes with something monstrous. 

  
  


“Oh my, does...doesn’t that ache? Like...badly?” is all he managed to get out. It’s suddenly _way_ too hot in here for both of them.

  
  


Senku gives a dry chuckle and throws his head back in deliriousness. This shit was kicking in rapidly and he had a feeling about how to fix it, but he wasn’t ready to verbalize it just yet. His eyes clouded over just as his manhood suddenly twitched, making his body rack with shivers. Fuck, fuck, fuck, fuck!

  
  


“Gen, I need you to help me. Seriously. I can’t explain right now, but I want something in me or on me—I don’t know but it needs to be done quickly or I might go insane.” He rasps out on the verge of losing consciousness again. 

  
  


Gen leans forward at full attention and hovers just above his friend’s chest. His cheeks flush with realization and almost cringes at his next words. 

  
  


“I’m not sure how you prefer it but I...er...I don’t exactly have the...um...facilities to be on top.” Shoot, why is he even considering this. He’s never had any romantic feelings for Senku...maybe? He doesn’t know. There’s barely time for such thoughts in this stone world so he hasn’t had much time to consider it. Of course, Senku is handsome and toned in a scrawny way, that’s not the issue here. 

  
  


He would like to consider the strange-haired man a close friend, maybe even a best friend. What if...what if he complies and after all of this is over—what if Senku is disgusted in him for doing so? He could picture the condescending look now and it made his throat terribly dry and his eyes prickle with fresh tears. 

  
  


His inner doubts don’t even have the time to consume him before he feels his body being pressed down by sudden force. His head abruptly makes contact with the ground and he whimpers a bit before glancing and greeting the hungry eyes above his. Their faces are so close and Gen can feel the man’s breath tickling his lips as if it’s saying “hello.” With just the tilt of his head, they would be kissing but would that be crossing a boundary? Technically sex would be hurdling over that boundary but would it count in this circumstance? He doesn’t fucking know! All he knows is that his own dick is now expressing gratitude at this close encounter.

  
  


“I-it’s fine. I’ll be on top or whatever. How...how should I start?”

  
  


The question doesn’t register until much later for Gen. How? What does he mean? Is there another way to start something like this? He nervously smiles before averting his eyes to any corner of the room hoping to ease some of the tension in the tight space. 

  
  


“Senku-chan, have you ever done this...with a man before?” 

  
  


Senku blushes with a huff.

  
  


“Or you know...at all?”

  
  


Senku looks away with a ‘tsk’. 

  
  


Bingo. 

Gen isn’t entirely sure how to go about this. It’s not often you have to give “the talk” to your suddenly sex-starved best friend. In a funny way, it’s almost like teaching a bird without wings about flight. Where exactly do you begin? How do you explain without being confusing or condescending?

  
  


“ _Gen.”_

  
  


The urgent tone in Senku’s voice manages to pull him together for this one moment. He swallows harshly and mentally begs for forgiveness from any gods above them. There’s hardly little any room for error as he crashes forward and catches those plump lips with his own. 

  
  


The feeling hits Senku’s dick like a freight train. The sudden sparks and friction against his mouth muscles is enough to make him dizzy all over again. Everything is too much and not enough all rolled up into one big ball of sexual tension. He swears he hears a low mewling sound and—by the gods it’s him! Heat rushes to his face but he can’t seem to contain his already pleasured noises. 

  
  


He’s kissed plenty of people before so why the hell does this feel any different? Well...maybe only a few people.

Perhaps…

  
  


Perhaps one person. 

  
  


In elementary school...by accident.

  
  


And it was gross. But that’s not the point. He knows the human body inside and out, he knew all about the stupid chemicals that overtake your senses when you kiss but he didn’t know it felt this good. His knees wobbled as he fell forward onto his elbows. Boy, was he in for a wild time. 

  
  


Gen takes this opportunity to slide his nimble fingers to his companion's cheek, brushing them lightly against the skin, and back down to his neck where he lays a faint palm against the base of his neck. The kiss feels like it’s lasted for hours when in reality it’s only been ten or twelve seconds. 

  
  


Senku breaks apart first. Gasping. Panting. Hot.

  
  


There wasn’t even a brief pause before Gen registered that fiery look in his eyes. He was asking what was next. And as an answer, Gen got up and flipped them over so that he was straddling the younger man’s hips. He’d seen the scientist at many different angles but none of them made his stomach flutter like this one. 

  
  


“Shit. Senku-chan you look delightful from up here. If only this cloak wasn’t getting in the way.” He outright purred and hooked his finger in the article of clothing. Senku was far beyond the usage of words so he bucked his hips as if urging him to do it. Gen wasn’t a man that denied requests so he was more than happy to slip the fabric off of his pale shoulders and shimmy it up until it came to a rest beside their warm bodies. 

  
  


Senku wasn’t ripped by any means but that didn’t mean Gen’s arousal wasn’t affected by the lean cut of meat beneath him. Beautiful collarbone, beautiful perky nipples and wow—! One mole barely visible upon first glance just above his right pectoral. Gen fights the urge to lean down and kiss it as he disrobes himself. 

  
  


There they are. Naked. With each other. 

  
  


Senku tries to push his aberrant fear out of the way for even just a second. This is nothing to be afraid of, but why does it feel like his heart just might explode. He’ll be damned if he croaks before Kaseki! To distract or engage his thoughts, he doesn’t know which, he leans up for one last kiss before propping his legs up. Gen leans down on them and spreads his legs wide as if to show off his jewels to the man. He’s almost as stiff as Senku and pretty soon he’s going to start needing his own friction. 

  
  


“Senku. Unfortunately there’s not yet any lube in this stone world—well before that I’m not a woman,” he laughs, “so I need you to cover your index and middle fingers with as much spit as possible. Can you do that?” The question is barely out of his mouth before Senku is delving his digits into his cavern, prodding and scooping as much as he can before removing them and placing one on top of Gen’s fluttering hole. 

  
  


They hold their breath for a moment before Senku inches his index finger into the tight ring of muscle. Tight is an understatement as he has to twist and turn his finger to even get to the second knuckle, but when he gets there Gen lets out a strangled noise. His toes are curling in delight and he’s trying to relax as much as he can but it’s been _so_ long since...since he’s had anything really. He watches as Senku focuses on getting his middle finger in there and the slight stretch and burn is already wearing him out. He thinks he hears the man beneath him grunt in approval but the thought is lost as the fingers inside him scissor his opening apart. 

  
  


Surely he won’t come just from this? He bites his lip in concentration and lets sexual nature fulfill its duty. The scissoring is now bearable and he cranes his neck to see Senku breaking a sweat from only trying to do this much. It’s endearing really. He steadies his posture and tells Senku to feel for a padded spot that doesn’t feel like anything else. Senku nods in affirmation when he finds it. He tells him to crook his fingers upwards.

  
  


That did it.

  
  


The moan? cry? scream? Whatever the fuck it was that left Gen’s, glossy, spit-slicked lips make Senku _curse._ Like a full on enchantment. He single-handedly put every sailor to shame with the string of foul words and dirty promises he uttered aloud. The power this man had over him was astonishing. He slipped his fingers out only to ram them back in, pumping at a pace that he would definitely feel in his arm later. The way Gen’s body twitched and spasmed was mind-boggling. He eyed the steady stream of pre-cum dripping from his tip and he swears if he wasn’t so occupied with making Gen cum on his fingers he would’ve taken him into his mouth.

  
  
  


Gen’s insides were nearly mush and he hadn’t even had the real thing yet. He must be getting old. Each task is harder than the last but he manages to convince Senku to slow down. The coil in his stomach is subsiding for now but his heart is yearning for one thing and one thing only. He slides down off of Senku’s body and takes his throbbing girth into his mouth without warning and hollows out his cheeks. The man is a machine as he simultaneously takes Senku to the hilt, fondles his sack and plays with his right nipple. 

  
  


_“_ Mmf—Gen! Please..ah..fuck!”

  
  


Senku’s whines get more needy and heady by the second and they’re melting Gen’s brains quite literally as he tries to hold himself together. It’s like he’s forgotten where he his and what’s been happening up until now. His ethereal plane of existence is shattered when Senku’s stomach tightens and his legs begin to shake. 

  
  


Gen rises not a millisecond later and with a very literal tongue and cheek smile. His eyes narrow with amusement as he rests both of his hands on either side of Senku’s pelvic bone. It’s a fucking delicious sight to see: a near purpling tip, shaft soaked in love juices, a face flushed with denied pleasure, and they’re all attached to a genius. It almost makes him sing to the heavens.

  
  


Almost. 

  
  


He has something else he wants to do first. While Senku is catching his breath, he reaches behind himself and checks one more time to make sure he’s prepped enough. Even he doesn’t trust whatever homemade solution Senku would concoct for a torn anus. Once he’s confirmed that he’s ready, he rises back to his straddling position but decides at the last minute to turn so that his ass is directly facing the man. If it’s really his first time, why not give him a show?

  
  


He hears the sharp intake of breath from behind him as Senku notices the plump derrière before him. Gen has draped his arms over Senku’s knees and is hovering above his cock with such poise. It looks like he’s been waiting for it...long before this. Maybe it’s the chemicals buzzing through his system or his natural instincts but Senku takes his hand and lands a harsh slap to Gen’s right asscheek. He watches with awe as the soft flesh jiggles before settling down again. The only noticeable difference is the bright red mark plastered to his skin like a tattoo. 

  
  


It’s fucking sexy. 

  
  


Once again, his body flares up and he feels the hunger overtake his senses again. In the blink of an eye, he’s rubbing his weeping tip against Gen’s slick entrance for the first time. The feeling is immaculate and if he prods hard enough—

  
  
  
  
  


The head slips in. 

Senku is now a slave to his needs.

  
  
  
  


With a carnal rush of desire, Senku grips the older man’s hips and pushes him down with a force he wasn’t even aware he had. It feels too good. It’s fucking hot, wet and sloppy and the sight of Gen desperately trying to fuck himself on his cock should be illegal. 

  
  


“S-Senku... _ahn!_ So good, so deepfuckfuckfuck!”

  
  


He pumps his manhood into Gen’s velvet insides but the friction only makes his dick swell and throb. He’s grunting and growling louder than he’d like but it’s not like he can control it. He’s cursing at Gen and telling him how he’s taking his shaft so prettily, relishing in the squeaks and squelches that erupt when Gen clenches down in response to his dirty talk. The pace isn’t too quick, mainly because that damned mentalist is leading, but he can feel every vibrating breath he makes. 

  
  


They continue like this for a little while before Gen’s legs give out. He shrieks as he falls forward and off of Senku’s dick with a lewd _schlip._ The burning in his thighs doesn’t subside and he can barely catch his breath. He knows his hips are bruised and battered with handprints and his lower back is definitely going to be sore in the morning but he couldn’t care less. He wants more. 

  
  


And Senku will give it to him. 

  
  


The scientist has basically grasped the concept of this thing so it’s time to get down to the nitty-gritty. He grabs Gen’s shoulders and pushes him so that his back is laying atop his chest. With a slight shimmy, Senku is now positioned just a little bit lower so that his own head is lying just underneath Gen’s neck. An optimal drilling position if he does say so himself.

  
  


“Spread your legs and hold ‘em for a bit.”

  
  


Without hesitation, Gen does as he’s told while ignoring the slight sting in his tendons. There are a few bated breaths as Senku smacks his member against his fluttering hole and eases it into home base. The feeling of being full again overwhelms him and his back is arching in response to the prominent stretching of his asshole. He feels his own hands being replaced by Senku’s.

  
  


“Senku-chan for a virgin you sure seem to know a lot about this position.” Gen teases, moving one hand backward to cup the man’s face and the other to stroke his own prick. Senku barks out a laugh at this and with the firm grip he has on Gen’s thighs, he raises them so that they’re nearly touching his shoulders. Senku props his knees up to get some even leverage on the soily ground. 

  
  


“I said I was a virgin...not a Saint.”

  
  


There’s no time for him to call his bluff because Senku is now promptly splitting Gen open on his fucking cock. Gen is positive he’s going insane because he can practically hear himself babbling away. Like a Christian praying for good health, he shouts and hollers to the skies only to run out of breath and repeat the process. Their collective sweat is making everything sticky and he can hear the slap of Senku’s balls against his ass like velcro. It’s mesmerizing. Deafening. Ravishing.

  
  


Cumming.

  
  


What?

  
  


So focused on the feeling of being pounded into oblivion, Gen apparently failed to realize that he was reaching his peak. It hadn’t even been that long, he can’t possibly be a minute man! He tries to will himself to stop but it’s no use. He’s going to prematurely cum all over himself. His cock twitches shamefully.

  
  


That sounds hot as fuck. 

  
  


So he lets it happen. With an airy moan, he shoots his load all over himself. It comes out in watery opaque ropes and splashes against his chest, chin, and face but not even that deters the man below him. Senku keeps blowing his back out like his life depends on it. He doesn’t even acknowledge the violent shaking in Gen’s legs. 

  
  


“Did you just orgasm?”

  
  


Gen is beyond words so he only whines in response. So the bastard did notice. His concern clearly was short-lived as he continued hitting Gen’s prostate like this was some sexual game of darts. The overstimulation was all too much so he clamped down on Senku’s rod like his life was in danger. 

  
  


Senku feels the new pressure being added to his organ and he groans in response. He can’t believe he’s gone 18 years of his life without experiencing this! After all of this is over and he’s saved humanity, he’s going to build a time machine and pummel some sense into his 17-year-old self. The real deal is definitely better than reading about it in textbooks. 

  
  


His speed never faltered and his ego only inflated as he relished in the sweet sounds coming from his partner. God, he’s so damn cute. Senku felt all of it when he came on his dick and he’s 10 billion percent sure he’d rather die than stop drilling into his tight cavern. Aphrodisiac or not, his body was screaming at him to keep going and give his all in this one moment. 

  
  


“Gen-kun.. _shit_. You feel s-so fucking good. ‘m gonna cum soon, sit tight.”

  
  


As if he could go anywhere. Misty-eyed and close to the edge again, Gen fiddles with his left nipple while his other hand lays atop Senku’s hand which is clutching his right thigh. He rubs his small fingers over the long fingers and wishes they were in his mouth. He wants to suck on them and let them explore his mouth while he gets used like a rag doll. 

  
  


He shakily pries the hand from his thigh and only for a moment does Senku’s pace stutter. As if saying “it’s okay,” Gen continues to move the hand all the way over his lips. He feels Senku’s eyes on him and can’t help the devilish smile that tugs on his face. He lifts a finger to his plush lips and kisses it once, twice and then places it into his mouth accompanied by a quick nip. 

  
  


“You’re so fucking—! Fine, be like that then. I don’t wanna hear any complaints later.”

  
  


Gen wouldn’t even know how to start a complaint because the moment Senku shoved two of his long fingers down his throat was when he felt a stirring deep in his guts. A feeling so primal latched on to his senses and the choking feeling made his eyes roll to the back of his head. This was it. This was euphoria. 

  
  


Senku heard it before he saw it. The muffled cry of Gen moaning around his fingers. The loud pattering of white fluid spraying from his dick. Then he saw it. The seed cascading down Gen’s shaft and chest and how it dripped to the ground beneath them. The completely fucked out expression he held on his face.

  
  
  
  


Ecstasy.

  
  
  
  


Senku launched himself deep as he could before he painted the magician’s insides. With curling toes and a vice-like grip around the thigh he was holding, he let out a low groan that was borderline animalistic. 

  
  


His. His. His. 

  
  


Gen’s ass. Gen’s cum. Gen’s moans. Gen’s smile. 

  
  


He yearned for it all in that one moment. His body quaked and spasmed from the sheer force of his orgasm. And just like that, he was spent. He fucked himself inside a few more times, lazily riding out his high and letting the drowsiness blanket his body. He hadn’t even registered how tight he was squeezing until Gen’s was rapidly tapping his face, trying to catch his attention.

  
  


Startled, he released his hold and allowed the older man to breathe as he rasped and coughed. Gen rolled over on the ground once he gathered himself and laid face-first into the covered soil. He couldn’t muster the power to think, let alone speak, so they sat in silence for what felt like an eternity. 

  
  


The spring breeze ruffled the flaps of the hut yet they still did not move. 

  
  
  
  
  
  
  
  


“Hey.”

  
  


“Hm?”

  
  


“Do you hate me now?”

  
  


“Why would I?”

  
  


“Well you didn’t exactly express interest in anybody, let alone men, so I thought maybe you would be mad afterward.”

  
  


Senku doesn’t reply this time and Gen surprisingly isn’t scared. He doesn’t feel like crying...or maybe it’s because he legitimately has nothing left in him. But he can accept whatever decision Senku makes for himself. He smiles softly.

  
  
  


Senku rolls over on his side so he can get a clear view of Gen’s beat-up form, spread like a starfish. 

  
  
  


“I...I think I like you. Well a lot more than I do most people.”

  
  


Oh, screw that, Gen was just putting on a brave face. If Senku rejected him his heart was going to be in fucking shambles. He lets out a sigh of relief at the reaffirmation and turns his head so that they’re making eye contact.

  
  


“But…”

  
  


Oh dear lord. His moment of peace is being invaded by this stupid conjunction. But?? But what?!

  
  


“I have a habit of researching things I like...and I’m not too sure I know _everything_ about you.”

  
  


How preposterous! Gen tells him damn near everything that has happened in his life, so it’s up to him to listen! He opens his mouth to protest but Senku cuts him off with his next words.

  
  
  


“Sure, I know that you love gagging on my fingers but I wanna know what else makes you moan.” Senku’s digits are now lightly tracing patterns on Gen’s back and his hand manages to slide lower

  
  
  


and lower 

  
  
  


and yet lower still...until he’s grabbing his asscheek. 

  
  


He pulls it apart from its neighbor and the cold air against his used hole causes Gen to shudder. Eyes narrowed and smiling maniacally, Senku feels his cock starting to swell with want again. 

  
  


Gen sees it and his heart stammers in his chest.

  
  
  
  
  
  
  


“Mind if I collect some data?”

**Author's Note:**

> Hi! Thank you once again for reading! I hope you enjoyed this work and that you support my other works as well! Comments and Kudos are greatly appreciated and if you have any problems please voice them!
> 
> Want to be friends or co-write together? Message me on here or instagram @udonszn


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